Meter electronics and methods for generating a drive signal for a vibratory flowmeter

• US 7,983,855 B2
• Filed: 09/13/2006
• Issued: 07/19/2011
• Est. Priority Date: 09/20/2005
• Status: Active Grant

• Current Assignee: Micro Motion Incorporated (Emerson Electric Company)
• Original Assignee: Micro Motion Incorporated (Emerson Electric Company)
• Inventors: Cunningham, Timothy J., McAnally, Craig B, Mansfield, William M
• Primary Examiner(s): Nghiem; Michael P
• Assistant Examiner(s): Ngon; Ricky
• Application Number:
  US12/066,910
• Publication Number:
  US 20080223148A1
• Time in Patent Office: 1,770 Days
• Field of Search: 702/45, 702/48, 702/50, 702 54- 56, 702/137, 738/610.1, 738/610.4, 738/611.8, 732/00
• US Class Current: 702/45
• CPC Class Codes: G01F 1/8413 means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments
• CPC Class Codes: G01F 1/8436 signal processing
• CPC Class Codes: G01F 1/8477 with multiple measuring conduits
• CPC Class Codes: G01F 15/024 involving digital counting

Abstract

A meter electronics (20) for generating a drive signal for a vibratory flowmeter (5) is provided according to an embodiment of the invention. The meter electronics includes an interface (201) and a processing system (203). The processing system is configured to receive the sensor signal (201) through the interface, phase-shift the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal, determine a phase shift value from a frequency response of the vibratory flowmeter, and combine the phase shift value with the sensor signal (201) and the phase-shifted sensor signal in order to generate a drive signal phase (213). The processing system is further configured to determine a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal, and generate a drive signal amplitude (215) based on the sensor signal amplitude (214), wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

Claims

1. Meter electronics (20) for generating a drive signal for a vibratory flowmeter (5), comprising:

an interface (201) for receiving a sensor signal (210) from the vibratory flowmeter (5); and

a processing system (203) in communication with the interface (201) and configured to receive the sensor signal (210), phase-shift the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal, determine a phase shift value (θ

) from a frequency response of the vibratory flowmeter (5), combine the phase shift value (θ

) with the sensor signal (210) and the phase-shifted sensor signal in order to generate a drive signal phase (213), determine a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal, and generate a drive signal amplitude (215) based on the sensor signal amplitude (214), wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

2. The meter electronics (20) of claim 1, wherein the phase-shifting is performed by a Hilbert transform.

3. The meter electronics (20) of claim 1, with the phase shift value (θ

) comprising a compensation value.

4. The meter electronics (20) of claim 1, with the determining the phase shift value (θ

) comprising linearly correlating the frequency response to a frequency/phase relationship in order to produce the phase shift value (θ

).

5. The meter electronics (20) of claim 1, with the determining the sensor signal amplitude (214) comprising:

receiving an Acosω

t term representing the sensor signal (210);

generating an Asinω

t term from the phase-shifting;

squaring the Acosω

t term and the Acosω

t term; and

taking a square root of the sum of the Acosω

t squared term and the Asinω

t squared term in order to determine the sensor signal amplitude (214).

6. The meter electronics (20) of claim 1, with the generating the drive signal amplitude (215) further comprising:

comparing the sensor signal amplitude (214) to an amplitude target (216); and

scaling the sensor signal amplitude (214) in order to generate the drive signal amplitude (215), with the scaling being based on the comparing of the sensor signal amplitude (214) to the amplitude target (216).

7. The meter electronics (20) of claim 1, further comprising chirping the drive signal at a startup of the flowmeter (5).

8. The meter electronics (20) of claim 1, further comprising chirping the drive signal at a startup of the flowmeter (5), with the chirping comprising sweeping through two or more frequency ranges until the flowmeter (5) starts.

9. The meter electronics (20) of claim 1, further comprising linearizing the drive signal.

10. The meter electronics (20) of claim 1, further comprising:

calculating a second amplitude using peak detection;

comparing the sensor signal amplitude (214) to the second amplitude; and

detecting broadband noise on a pickoff sensor if the second amplitude is higher than the sensor signal amplitude (214).

11. A method for generating a drive signal for a vibratory flowmeter (5), the method comprising:

receiving a sensor signal (210) from the vibratory flowmeter (5);

phase-shifting the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal;

determining a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal, with determining the sensor signal amplitude (214) comprising;

receiving an Acosω

t term representing the sensor signal (210);

generating an Asinω

t term from the phase-shifting;

squaring the Acosω

t term and the Asinω

t term; and

taking a square root of the sum of the Acosω

t squared term and the

Asinω

t squared term in order to determine the sensor signal amplitude (214);

generating a drive signal amplitude (215) based on the sensor signal amplitude (214); and

generating a drive signal including the drive signal amplitude (215).

12. The method of claim 11, wherein the phase-shifting is performed by a Hilbert transform.

13. The method of claim 11, with the generating the drive signal amplitude (215) further comprising:

comparing the sensor signal amplitude (214) to an amplitude target (216); and

scaling the sensor signal amplitude (214) in order to generate the drive signal amplitude (215), with the scaling being based on the comparing of the sensor signal amplitude (214) to the amplitude target (216).

14. The method of claim 11, further comprising:

determining a phase shift value (θ

) from a frequency response of the vibratory flowmeter (5);

combining the phase shift value (θ

) with the sensor signal (210) and the phase-shifted sensor signal in order to generate a drive signal phase (213); and

including the drive signal phase (213) in the drive signal, wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

15. The method of claim 11, further comprising:

linearly correlating the frequency response to a frequency/phase relationship in order to produce a phase shift value (θ

);

combining the phase shift value (θ

) with the sensor signal (210) and the phase-shifted sensor signal in order to generate a drive signal phase (213); and

including the drive signal phase (213) in the drive signal, wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

16. The method of claim 11, further comprising chirping the drive signal at a startup of the flowmeter (5).

17. The method of claim 11, further comprising chirping the drive signal at a startup of the flowmeter (5), with the chirping comprising sweeping through two or more frequency ranges until the flowmeter (5) starts.

18. The method of claim 11, further comprising linearizing the drive signal.

19. The method of claim 11, further comprising:

calculating a second amplitude using peak detection;

comparing the sensor signal amplitude (214) to the second amplitude; and

detecting broadband noise on a pickoff sensor if the second amplitude is higher than the sensor signal amplitude (214).

20. A method for generating a drive signal for a vibratory flowmeter (5), the method comprising:

receiving a sensor signal (210) from the vibratory flowmeter (5);

phase-shifting the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal;

determining a phase shift value (0) from a frequency response of the vibratory flowmeter (5); and

combining the phase shift value (θ

) with the sensor signal (210) and the phase-shifted sensor signal in order to generate a drive signal, wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

21. The method of claim 20, wherein the phase-shifting is performed by a Hilbert transform.

22. The method of claim 20, with the phase shift value (θ

) comprising a compensation value.

23. The method of claim 20, with the determining the phase shift value (θ

) comprising linearly correlating the frequency response to a frequency/phase relationship in order to produce the phase shift value (θ

).

24. The method of claim 20, further comprising:

determining a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal;

generating a drive signal amplitude (215) based on the sensor signal amplitude (214); and

including the drive signal amplitude (215) in the drive signal.

25. The method of claim 24, further comprising:

calculating a second amplitude using peak detection;

comparing the sensor signal amplitude (214) to the second amplitude; and

detecting broadband noise on a pickoff sensor if the second amplitude is higher than the sensor signal amplitude (214).

26. The method of claim 20, further comprising:

receiving an Acosω

t term representing the sensor signal (210);

generating an Asin ω

t term from the phase-shifting;

squaring the Acosω

t term and the Asinω

t term;

taking a square root of the sum of the Acosω

t squared term and the Asinω

t squared term in order to determine the sensor signal amplitude (214);

generating a drive signal amplitude (215) based on the sensor signal amplitude (214); and

including the drive signal amplitude (215) in the drive signal.

27. The method of claim 20, with the generating the drive signal amplitude (215) further comprising:

receiving an Acosω

t term representing the sensor signal (210);

generating an Asinω

t term from the phase-shifting;

squaring the Acosω

t term and the Asinω

t term;

taking a square root of the sum of the Acosω

t squared term and the Asinω

t squared term in order to determine the sensor signal amplitude (214);

comparing the sensor signal amplitude (214) to an amplitude target (216);

scaling the sensor signal amplitude (214) in order to generate the drive signal amplitude (215), with the scaling being based on the comparing of the sensor signal amplitude (214) to the amplitude target (216); and

including the drive signal amplitude (215) in the drive signal.

28. The method of claim 20, further comprising chirping the drive signal at a startup of the flowmeter (5).

29. The method of claim 20, further comprising chirping the drive signal at a startup of the flowmeter (5), with the chirping comprising sweeping through two or more frequency ranges until the flowmeter (5) starts.

30. The method of claim 20, further comprising linearizing the drive signal.

31. A method for generating a drive signal for a vibratory flowmeter (5), the method comprising:

receiving a sensor signal (210) from the vibratory flowmeter (5);

phase-shifting the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal;

determining a phase shift value (θ

) from a frequency response of the vibratory flowmeter (5);

combining the phase shift value (θ

) with the sensor signal (210) and the phase-shifted sensor signal in order to generate a drive signal;

determining a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal; and

generating a drive signal amplitude (215) based on the sensor signal amplitude (214), wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).

32. The method of claim 31, wherein the phase-shifting is performed by a Hilbert transform.

33. The method of claim 31, with the phase shift value (θ

) comprising a compensation value.

34. The method of claim 31, with the determining the phase shift value (θ

) comprising linearly correlating the frequency response to a frequency/phase relationship in order to produce the phase shift value (θ

).

35. The method of claim 31, with the determining the sensor signal amplitude (214) comprising:

receiving an Acosω

t term representing the sensor signal (210);

generating an Asinω

t term from the phase-shifting;

squaring the Acosω

t term and the Asinω

t term; and

taking a square root of the sum of the Acosω

t squared term and the Asinω

t squared term in order to determine the sensor signal amplitude (214).

36. The method of claim 31, with the generating the drive signal amplitude (215) further comprising:

comparing the sensor signal amplitude (214) to an amplitude target (216); and

scaling the sensor signal amplitude (214) in order to generate the drive signal amplitude (215), with the scaling being based on the comparing of the sensor signal amplitude (214) to the amplitude target (216).

37. The method of claim 31, further comprising chirping the drive signal at a startup of the flowmeter (5).

38. The method of claim 31, further comprising chirping the drive signal at a startup of the flowmeter (5), with the chirping comprising sweeping through two or more frequency ranges until the flowmeter (5) starts.

39. The method of claim 31, further comprising linearizing the drive signal.

40. The method of claim 31, further comprising:

calculating a second amplitude using peak detection;

comparing the sensor signal amplitude (214) to the second amplitude; and

detecting broadband noise on a pickoff sensor if the second amplitude is higher than the sensor signal amplitude (214).